Apparatus for forming sheet metal



June 2, 1964 L. L. HOCK 3,135,313

APPARATUS FOR FORMING SHEET METAL Filed June 23. 1961 2 Sheets-Sheet 1INVENTOR. LAWRf/VC L. H

ATTORNEYS June 2, 1964 L. 1.. HOCK 3,135,313

APPARATUS FOR FORMING SHEET METAL Filed June 23, 1961 2 Sheets-Sheet 2INVENTOR.

' AAWR /WEL Hoax A TTORNEVS United States Patent H 3,135,313 APPARATUSFOR FORMING SHEET METAL Lawrence L. Hock, Snyder, N.Y., assignor toNiagara Machine & Tool Works, Bufialo, N.Y. Filed lune 23, 1961, Ser.No. 119,091 7 Claims. ((11. 153-21) This invention relates to a methodof and apparatus for forming sheet metal parts by a succession of metalbending or forming steps carried out by successive strokes of a pressbrake or other power press provided with a single set of complementarypunch and die members.

The method and apparatus of the present invention is directed primarilyto the manufacture of a particular sheet metal product but one which isusually and customarily manufactured locally on a relatively smallscale.

These articles are known in the art as standing S-cleats and areemployed by sheet metal Workers mainly in joining square or rectangularduct sections in end to end relation.

Various economic factors dictate the general practice of manufacturingS-cleats on a relatively small scale local basis. In any event,presently known and used prior art methods generally entail a series ofdie forming operations performed in a series of different dies whichmethods involve multiple setting-up operations, multiple handling of thework pieces, and other inefiiciencies, not to mention the cost of theseveral separate sets of dies required to perform the successive formingsteps of such prior art methods.

The present invention provides a punch and die construction and a novelmethod of employing the same whereby a workman merely places theworkpiece successively in various positions in a single die structureand effects successive identical strokes of the press brake or otherpower press to perform a series of bending or forming operations withoutany change in dies, set-up, press stroke or any other condition ofadjustment or operation.

The workman picks up a rectangular blank of flat sheet metal oranalogous material, subjects the same to various bending or formingoperations by successive strokes of the press, in the present instancefive such strokes, and lays aside the finished standing S-cleat.Furthermore, the cooperating punch and die members disclosed herein foreffecting the novel method of the present invention are extremely simpleas to the profiles or configurations of the complementary punch and diesurfaces.

' Since the standing S-cleats produced by the present method andapparatu are of random length and the forming affects only thetransverse cross section of the workpiece, the work is usually performedin press brakes and the punches and die are merely continuous integralbars formed with the desired complementary forming surfaces, as isgenerally the case in punches and dies employed in press brakes.

A single specific die and punch structure and a specific succession offorming steps are illustrated in the accompanying drawings and describedin detail in the following specification by way of example but it is tobe understood that the principles of the present invention are notlimited precisely thereto nor otherwise than as defined in the appendedclaims.

In the drawings:

FIG. 1 is a transverse cross-sectional view through one form of a pairof cooperating punch and die members of the present invention with thepunch raised and a workpiece in position for a first forming operation;

FIG. 2 is a View similar to FIG. 1 but showing the punch in loweredposition wherein the first forming operation has been effected;

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FIGS. 3, 5, 7 and 9 are similar to FIG. 1, showing the punch member inraised position but showing workpieces disposed for a series ofsubsequent forming operations; and

FIGS. 4, 6, 8 and 10 are views similar to FIG. 2, showing the punchmember in lowered position with respect to the die member and showingthe completion of such subsequent series of forming operations.

Like characters of reference denote like parts throughout the severalfigures of the drawings and the specific arrangement and contours of thepunch and die members will now be described. Referring particularly toFIG. 1, a die member 15 is provided with a V groove 16 in its uppersurface. In the illustrated instance the rear surface of the V groove ismore vertically disposed than the front surface, as clearly depicted inthe drawing.

The fiat upper portion of the die surface rearwardly of the V groove 16,designated 17, is sloped slightly so that the same is substantially at aright angle to the rear surface of the V groove 16. The front topsurface of die block 15 forwardly of V groove 16 may be generallyhorizontal, as shown.

The punch member is designated 20 and is provided with a V formation 21which is complementary to the V groove 16. The under surface of punchmember 20 just rearwardly of the V formation 21, designated 22 in FIG.1, is at right angles to the rear surface of V formation 21 and isconsequently parallel to the upper rear surface 17 of die block 15.Rearwardly of the surface 22 punch member 20 is offset to provide afurther surface 23 at right angles to the rear surface of V formation 21and parallel to the surface 22 of the punch memher.

As shown in FIG. 2, the punch and die members 20 and 15 may be providedwith conventional tongues designated 25 and 26 respectively for securingthe punch and die members in a conventional press brake or like powerpress. The foregoing relatively simple punch and die set-up is adaptedto perform, in the present instance, a series of five successive bendingor metal-forming operations on a single workpiece With a single handlingthereof and without any change in set-up to produce a finished S-cleatsuch as is shown at 28 in FIG. 10.

These successive operations are performed by successive press strokesand despite the differing character of the successive bending operationsthe design and arrangement of the punch and die members is such that thevarious operations are each performed with like strokes of the punchmember. That is, the punch member descends a constant fixed distanceinto the die member on each stroke so that a workman need onlysuccessively reposition the workpiece between each bending or formingoperation until the five operations of the present set-up have beenperformed and the finished piece produced.

It is to be understood that S cleats are generally elongated and ofvarious lengths and that the several crosssectional views thereof shownherein are transverse. Accordingly, FIG. 1 shows a rectangular blank orworkpiece 30, the width or smaller dimension thereof being shown in FIG.1 in the initial position of the blank for the first forming operation.

The proportions of the V groove 16 and complementary V formation 21,their relative positions considered from front to rear (from left toright as viewed in FIG. 1), and the depth of travel of the punch member20, are all such that in the lower or closed position of the punchmember the rear or left-hand face of the V formation 21 as viewed in thedrawings and the corresponding left-hand or rear face of the groove 16are parallel and spaced approximately a metal thickness whereas thefront or right-hand faces of the groove 16 and V formation 21 arelikewise parallel but at a substantially greater distance from eachother. Furthermore, the ledge 22 of the punch member 2b is arranged toapproach the corresponding upper face portion 17 of die member 15 towithin substantially one metal thickness when the punch is in itslowermost position.

In the first operation as shown in FIG. 2, an oblique flange 31 isformed along one edge of workpiece 30, the internal radius of the flangebeing of course determined by the radius of the apex of the ridge or Vformation 21 of the punch member.

The workman then places the flanged workpiece 34 in the position shownin FIG. 3 and because of the relative spacing of the front face of ridgeformation 21 and the corresponding surface of V groove 16, a subsequentpress stroke produces a rounded return bent formation, as clearlyillustrated in FIG. 4.

The operation illustrated in FIGS. 5 and 6 is substantially the same asthat of FIGS. 1 and 2 excepting that the opposite edge of the blank orworkpiece 3% is obliquely flanged as at 35 and in the present instancein the opposite direction.

In the succeeding forming operation illustrated in FIGS. 7 and 8 theworkpiece is formed into substantially Z shape and at the same time theoblique flange 35 is formed into return bent form, again somewhatrounded as in the case of the return bent formation of flange 31, inthis instance by reason of the relative spacing of the surface 23 of thepunch member with respect to the companion surface 17 of the die block15.

The generally 2 form of the workpiece produced as illustrated in FIG. 8provides a right-angle bend at the upper rear edge of the V groove 16which produces substantially the finished form of a medial flange 37 ofthe finished S cleat, as shown in FIG. 10. At the same time the apex ofthe ridge formation 21 of the punch member produces an acute angleformation which is placed in position with respect to die block 15, asillustrated in FIG. 9, whereby a subsequent downward movement of punchmember 20 produces a further return bent formation to produce thesubstantially T form of the finished S cleat illustrated in FIG. 10.

Here again the spacing of the front face of ridge formation 21 of punchmember 20 and the corresponding front face of V groove 15 in die block15 results in a rounded edge in the return bent formation. The frontface of punch member if) is notched at the base of the V formation 21 toclear the workpiece as the same flanges up in the various operations andto provide a ledge 38 which, in the final forming operation illustratedin FIGS. 9 and 10, engages the return bend which was formed in theoperation illustrated in FIGS. 1 and 2 and holds the workpiece againstslipping upwardly during the final forming operation illustrated in FIG.10. The finished S cleat is thus provided with three smoothly roundededges which by reason of their mode of formation are of substantiallythe same radius or thickness across the aforesaid return bends. I

I claim: H

1. In a die for forming metal sheets, a die member having an uppersurface portion with a V groove therein,

a punch member generally complementary to said die surface having a Vformation adapted to enter the V groove of said die member, said membersbeing so proportioned that in closed position the complementary rearsurfaces of said V groove and V formation are parallel and spaced bysubstantially the thickness of a sheet to be formed therein and thecomplementary front surfaces are parallel and spaced a distance greaterthan twice said sheet thickness throughout the entire depth of said Vgroove, the surfaces of said members rearwardly of said V groove and Vformation being parallel to each other and at right angles to the rearsurfaces of said V groove and V formation.

2. In a die for forming metal sheets, a die member having an uppersurface portion with a V-groove therein, a punch member generallycomplementary to said die surface having a V formation adapted to enterthe V groove of said die member, said members being so proportioned thatin closed position the complementary rear surfaces of said V groove andV formation are parallel and spaced by substantially the thickness of asheet to be formed therein and the complementary front surfaces areparallel and spaced a distance greater than twice said sheet thicknessthroughout the entire depth of said V groove, the surfaces of saidmembers rearwardly of said V groove and V formation being parallel toeach other and at right angles'to the rear surfaces of said V groove andV formation and proportioned to be spaced substantially a sheetthickness when said members are in closed position.

3. In a die for forming metal sheets, a die member having an uppersurface portion with a V groove therein, said upper surface portionrearwardly of said V groove being substantially at right angles to thecontiguous rear wall of said V groove, a punch member generallycomplementary to said die surface having a V formation adapted to enterthe V groove of said die'member, said members being so proportioned thatin closed position the complementary rear surfaces of said V groove andV formation are parallel and spaced by substantially the thickness of asheet to be formed therein and the complementary front surfaces areparallel and spaced a distance greater than twice said she'et'thicknessthroughout the entire depth of said V groove, the surfaces of said punchmembers rearwardly of said V formation being parallel to the aforesaidrear upper surface portion of said die member and spaced therefromsubstantially a sheet thickness when the members are in closed position.

4. In a die for forming metal sheets, a die member having an uppersurface portion with a V groove therein, a punch member generallycomplementary to said die surface having a V formation adapted to enterthe V groove of said die member, said members being so proportioned thatin closed position the complementary rear surfaces of said V groove andV formation are parallel and spaced by substantially the thickness of asheet to be formed therein and the complementary front surfaces areparallel and spaced a distance greater than twice said sheet thicknessthroughout the entire depth of said V groove, the surfaces of saidmembers rearwardly of said V groove and V formation being parallel toeach other and at right angles to the rear surfaces of said V groove andV formation and proportioned to be spaced substantially a sheetthickness when said members are in closed position, one of said lastmentioned surfaces being stepped rearwardly to provide a rearward spacesubstantially greater than said sheet thickness space.

5. Apparatus for forming sheet metal articles comprising stationarymeans and means movable toward and away from the same, said stationarymeans including a die member having a surface portion. with a V-groovetherein, said movable means including a punch member having a Vformation adapted to enter the V groove of said die member, said membersbeing so proportioned that in closed position the complementary rearsurfaces of said V groove and V formation are parallel and spaced bysubstantially the thickness of a sheet to be formed therein and thecomplementary front surfaces are parallel and spaced a distance at leasttwice said sheet thickness throughout the entire depth of said V groove.

6. Apparatus for forming sheet metal articlescomprising stationary meansand means movable toward and away from the same, said stationary meansincluding a die member having a surface portion with a V groove therein,said movable means including a punch member having a V formation adaptedto enter the V groove of said die member, said members being soproportioned that in closed position the complemetary rear surfaces ofsaid V groove and V formation are parallel and spaced by substantiallythe thickness of a sheet to be formed therein and the complementaryfront surfaces are parallel and spaced at distance at least twice saidsheet thicktherein, said movable means including a punch member having aV formation adapted to enter the V groove of said die member, saidmembers being so proportioned that in closed position the complementaryrear surfaces of said V groove and V formation are parallel and spacedby substantially the thickness of a sheet to be formed therein and thecomplementary front surfaces are parallel and spaced a distance at leasttwice said sheet thickness throughout the entire depth of said V groove,the surfaces of said members rearwardly of said V groove and V formationbeing parallel to each other and substantially at right angles to therear surfaces of said V groove and V formation and spaced substantiallya sheet thickness when said members are in closed position, one of saidlast mentioned surfaces having an offset portion spaced rearwardly ofsaid V groove and formation to provide forming surfaces spaced at leasttwice said sheet thickness.

References Cited in the file of this patent UNITED STATES PATENTS658,077 Thomas Sept. 18, 1900 1,963,853 Jones June 19, 1934 2,383,133Kost Aug. 21, 1945 2,821,234 Robbins et al Jan. 28, 1958 2,847,052Hardman Apr. 12, 1958 2,908,315 Hellwig Oct. 13, 1959 3,034,559 SlaterMay 15, 1962 OTHER REFERENCES Cincinnati Press Brake Dies, Catalog D-3,page 17, The Cincinnati Shafer Co., Cincinnati, Ohio.

1. IN A DIE FOR FORMING METAL SHEETS, A DIE MEMBER HAVING AN UPPERSURFACE PORTION WITH V GROOVE THEREIN, A PUNCH MEMBER GENERALLYCOMPLEMENTARY TO SAID DIE SURFACE HAVING A V FORMATION ADAPTED TO ENTERTHE V GROOVE OF SAID DIE MEMBER, SAID MEMBERS BEING SO PROPORTIONED THATIN CLOSED POSITION THE COMPLEMENTARY REAR SURFACES OF SAID V GROOVE ANDV FORMATION ARE PARALLEL AND SPACED BY SUBSTANTIALLY THE THICKNESS OF ASHEET TO BE FORMED THEREIN AND THE COMPLEMENTARY FRONT SURFACES AREPARALLEL AND SPACED A DISTANCE GREATER THAN TWICE SAID SHEET THICKNESSTHROUGHOUT THE ENTIRE DEPTH OF SAID V GROOVE, THE SURFACES OF SAIDMEMBERS REARWARDLY OF SAID V GROOVE AND V FORMATION BEING PARALLEL TOEACH OTHER AND AT RIGHT ANGLES TO THE REAR SURFACES OF SAID V GROOVE ANDV FORMATION.